Gas tank relocation

[Chevy nutcase]

Was ordering a bunch of stuff to redo the floor, carpet and seatbelts in my 66 c10 and I want to relocate the gas tank and I have a question. I know one way this was done was to use a blazer tank which requires some modifications to be made to the bed crossmembers but do the kits offered by a variety of sites also require the same crossmember mods? I was thinking of getting my tank from Brothers/Holley and their site says very little on the subject and I don't see why a product specifically made for this would require cutting and welding.